Male infertility is one of the major factors causing infertility. According to the report of the World Health Organization (WHO) in 2,000, the global infertility rate was about 15%, in which male factors accounted for about 50%. Infertility rate in some countries in Europe is up to 30%. There are complex and various factors for male infertility, including abnormal and dysfunction of many factors, such as anatomy structure and function of the reproductive system, hormone regulation, the genetic material, and infection immunity.
Male infertility is not an independent disease, but resulted from the synthetic action of various diseases or multiple factors. Although the causes for male infertility are quite complex, the methods for routine semen detection are very limited at present.
Researches have shown that most reasons for male infertility are abnormal spermiogenesis or azoospermia. Sperms generated from human testis enter into the epididymis, be incubated and matured in the epididymis, while the function of sperms is gradually declined or even completely losted with the aging process.
A lot of studies about the function and regulation of the epididymis and testis are reported, however, so far, little has been known about the proteins (especially sperm localization proteins) expression pattern for the epididymis and testis from development to aging, not to mention the corresponding specific detection method. Therefore, it is urgent to seek male fertility-associated proteins which cause sperm aging and reduced fertility.